(1) Field of the Invention
The present invention relates to an electric connection block, in which terminals connecting an electrical component such as a fuse, a connector and so on to a circuit board are laminated and arranged in a plurality of layers.
(2) Description of the Related Art
FIG. 8 shows an example of circuit board assembly including a fuse block as a conventional electric connection block (see Japanese Patent Application Laid-Open No. 2006-333583).
A fuse block 77 includes: a fuse holder (i.e. block body) 78 made of electrically insulating resin; a plurality of L-shaped terminals 76, one end part of which is inserted in the fuse holder 78 and an opposite end part of which is soldered to a circuit board 73; a comb teeth-shaped busbar (not shown in the figure) made of metal inserted in the fuse holder 78; and a connector 80 for receiving power supply, which receives one side part of the busbar.
The fuse holder 78 mounts a plurality of blade-shaped fuses (not shown in the figure) in two steps up and down in parallel in a left-and-right direction. Corresponding to a pair of the terminals situated up and down of the fuse, respective tuning fork-shaped clamp terminal parts of the pair of the terminals situated up and down and a pair of the busbars situated up and down are received in receiving chambers 77a situated up and down. The connector 80 is connected to circuits of a battery power supply-side and of alternator power supply-side.
A circuit board assembly 71 includes: a circuit board 73 mounting various electronic components 72; the fuse block 77 connected to the front side of the circuit board 73 by the terminal 76; and a connector block 75 connected to both sides left and right of the circuit board 73 by a terminal 74. The circuit board 73 and each block 75, 77 are covered by a cover (not shown in the figure) made of electrically insulating resin situated up and down on a condition that an opening 75a, 77a-side of each block 75, 77 is exposed, thereby constructing a junction block.
Japanese Patent Application Laid-Open No. 2006-333583 described above shows an example in which a terminal holder is joined to the fuse holder 78 on a condition that L-shaped terminals 76 (instead of the busbars described above) are received in a terminal holder (not shown in the figure) made of electrically insulating resin in a plurality of steps. The circuit board 73 is provided with a copper layer (not shown in the figure) at a middle part thereof in a thickness direction.
FIG. 9 shows an example of a fuse block structure, in which clamp terminal parts 83-side of respective L-shaped terminals 82 is press-fit into and fixed to a horizontal hole part 81 of a fuse holder (i.e. block body) made of electrically insulating resin (for example, see Japanese Patent Application Laid-Open No. 2003-217437 as to the press-fitting of the terminal).
The hole part 81 is formed in a rectangular slit-shape. An electrically insulating part 84 of the block body is positioned between the respective hole parts 81. A projection 85 is provided at both sides of the terminal 82. The projection 85 is press-fit into the electrically insulating part 84 so as to prevent the terminal 82 from coming out.
Japanese Patent Application Laid-Open No. 2006-187050 discloses an example of a fuse block structure, in which a terminal is fixed to a fuse holder (i.e. block body) by insert molding instead of press-fitting. Japanese Patent Application Laid-Open No. 2004-282908 discloses an example of a fuse block structure, in which terminals (or busbars) are arranged on a wiring board per layer.
As for the fuse block (shown in FIG. 8) described in Japanese Patent Application Laid-Open No. 2006-333583, it is demanded that the terminals 76 are correctly positioned with respect to the fuse and the circuit board 73 while the terminals 76 are received in a terminal holder (not shown in the figure) in a plurality of steps and that the terminals 76 of the respective steps are assembled to the terminal holder securely with good workability.
As for the fuse block (shown in FIG. 9) described in Japanese Patent Application Laid-Open No. 2003-217437, there is a possibility that when a pitch between the terminals 82 is made small, the electrically insulating part 84 between the terminals 82 becomes thin, causing deterioration in press-fitting property of the terminals and in electrical insulating property between the terminals.
As for the fuse block (not shown in the figure) described in Japanese Patent Application Laid-Open No. 2006-187050, there is a problem that it is difficult to insert-mold the terminals simultaneously in two or more layers.
As for the fuse block (not shown in the figure) described in Japanese Patent Application Laid-Open No. 2004-282908, there is a possibility that when the terminals are arranged on a wiring board per layer, the number of components is increased, a structure of the fuse block becomes large, an accuracy of dimension between the terminals is deteriorated, and assembling property (connection property) between the fuse block and another component such as a fuse or a circuit board is deteriorated.
The problem or undesirable possibility described above may similarly take place even when an electrical component such as fusible link or a relay is used instead of a fuse and even when a connector is being connected instead of an electrical component.